1. Field of the Invention
This invention pertains to a device which accurately measures the yarn used by a flat bed knitting machine in order to measure stitch size.
2. Description of the Prior Art and Objectives of the Invention
The textile industry is an old and well established industry with many specialized machines and methods. One such machine is the flat bed knitting machine, which has existed in various forms for close to one hundred years. Presently, several variations are commercially available, such as the Z or XL series produced by NOVA of 1396 Walkup Avenue, Monroe, N.C. 28110. Other manufacturers include Protti, Stoll, and Universal. These machines, like other flat bed knitting machines are designed to efficiently knit collars for knit shirts such as those sold under the POLO.RTM. or IZOD.RTM. trademarks.
Such machines typically have one or two carriages, each with front and back camming mechanisms which drive needles positioned in a pair of needle tracks so as to knit a collar. Unfortunately, these carriages must be calibrated to provide identical stitch size in the collar. If one camming mechanism is out of calibration, i.e. making stitches of a size not uniform with the stitch size of the other camming mechanisms, the resulting collars created on the machine may unacceptably curl or otherwise fail to meet product requirements. In the past, stitch size has been visually examined by the technicians in order to approximate equivalent size. Additionally, stitch size determines how "loose" or "tight" a knitted fabric is, and is thus a quality control measurement.
In contrast to the flat bed industry, the circular knitting industry has long had a device which accurately measured the amount of yarn that was used to create a course around the knitting device. One such device is that disclosed in my U.S. Pat. No. 3,790,761 ('761) which uses a wand mounted wheel removably positioned proximate the yarn carrier to accurately measure yarn passing thereacross.
Important differences exist between the circular knitting machines and flat bed knitting machines. In contrast to a circular knitting machine which holds the carrier fixed relative to the needle bed, flat bed knitting machines move the carrier the length of the needle bed. Therefore, the wand mechanism of the '761 patent is an inappropriate device with which to measure the amount of yarn consumed since it would have to move with the carrier. Its hand-held nature would result in inaccurate readings. Likewise, in contrast to the circular knitting machines which maintain a relatively constant tension on the yarn being knit, flat bed knitting machines have widely varying tensions depending on the positions of the carriers.
Still further differentiating the two machines is the fact that in a circular knitting machine, there are always a fixed number of needles being used to form a course whereas in a flat bed machine, the number of needles may be varied to knit collars of different lengths. Thus, while techniques do exist which will measure stitch size, they are not easily adapted to the conventional flat bed knitting machine.
With the above concerns in mind, it is an objective of the present invention to provide a device which will accurately measure stitch size in a flat bed knitting machine.
It is a further objective of the present invention to provide a device which will help technicians make the stitch size of multiple carriages on a flat bed knitting machine uniform.
It is still a further objective of the present invention to provide a method of measuring stitch size on a flat bed knitting machine.
It is yet a further objective of the present invention to position a wheel to measure yarn on the carrier of a flat bed knitting machine.
It is another objective to provide an improvement on a flat bed knitting machine which uses magnets to effectively measure the amount of yarn used by a fixed number of needles.
These and other objectives and advantages will become readily apparent to those skilled in the art upon reference to the following detailed description and accompanying drawing figures.